Screw-driver.



A. N. BENDER.

SCREW DRIVER.

APPLICATION FILED SEPT. 26, 1907.

954,073. Pa en ed Apr. 5,1910.

F/GZ.

14 T TORNE Y5.

UNITED STATES PATENT OFFICE.

' ALBERT N. BENDER, or RAGINE, WISCONSIN, ASSIGNOR or ONE-HALF r JOHN c.

KLEIST, or MILWAUKEE, WISCONSIN.

SCREW-DRIVER.

Specification of Letters latent.

Patented Apr. 5, 1910.

Application filed September 28, 1907. Serial. No. 394,967.

To atl whom it may concern:

Be it known that I, ALBERT N. BENDER, residing in Racine, in the countyof Racine and State of Visconsin, have invented new and usefulImprovements in Screw-Drivers, of which the following is a description,reference being had to the accompanying drawings, which are apart ofthis specification.

This invention relates to improvements in screw drivers.

One of the objects of the invention is to provide a screw driver whichwill firmly clamp and hold a screw during the operation of driving it.

A further object of the invention is to provide means for securelylocking the screw driver to the screw after it has been clamped theretoand thereby remove any possibility of accidental disengagement.

A still further object is to provide a screw driver which may be usedfor boring holes for countersinking purposes.

lVith the above, and other incidental, objects in View, the inventionconsists of the parts, and combination of parts, and all equivalentsthereof.

In the accompanying drawings, in which similar characters of referenceindicate like parts: Figure 1 represents a side view of my improvedscrew driver engaging a screw, )itltS being broken away to show interiorconstruction; Fig. 2 is a view thereof taken at right angles to Fig. 1;Fig. 3 is a view of the clamping end of the screw driver; Fig. 4: is aview of the head of a screw adapted for use with this improved screwdriver; Fig. 5 is a view of a fragment of a round headed screw partly insection, also adapted for use with this improved screw driver; and Fig.6 is a view of a fragment of a modified form of screw driver'providedwith means for locking the screw clamping jaws to the screws.

Referring to the drawings, the numeral 8 indicates the shank of thescrew driver, the upper squared end of which maybe connected to asuitable handle, or to any suitable turning device. The lower end of theshank is provided with an enlargement 10 round in cross section andforming the.

head of the screw driver. The head is provided at diametrically oppositeportions thereof with recesses 11, 11 extending longitudinally thereof,and in the recesses are disposed fulcrumed clamping levers 12, 12,

the levers being fulcrumed to the sides of the head forming the recessesby means of pivot pins 13, 13. The lower extremities of the levers areprovided with inwardly inclined engaging jaws 14, 14: to convenientlyengage a screw particularly constructed therefor. The upper extremitiesof the levers project out of the recesses and are enlarged and roundedto form finger pieces 1.5, 15 to manipulate the engaging jaws. coiledspring 16 passes through an opening 17 in the shank 8 immediately abovethe head and its opposite ends engage the inner surfaces of the fingerieces of the clamping levers to normally orce them outwardly and to movethe engaging jaws inwardly. A. slot 18 extends through the head of thescrew driver adjacent to the pivotal connection of the clamping leversthereto, and provides the necessary space to accommodate the medialenlargement of the levers through which the pivotal pins pass.

The inwardly inclined engaging jaws 14k, 14 are wedge shaped andsharpened so as to firmly clamp the head of the screw to the screwdriver and also to adapt them for use in boring holes when it is desiredto countersink a screw head. The lower end of the head is provided witha concave recess 19 so that the screw driver may enga e round headedscrews as well as flat heade screws. v

It is very convenient at times to be able to lock the engaging leverswhile engaging a screw, and to accomplish this result I have provided alocking nut 20 threaded to an enlargement 21 disposed above the fingerportions of the engaging levers. The lower portion 22 of this lockingnut is tapered and the tapered portion is adapted to engage the innerupper edges of the finger pieces and to'force them outwardly when thenut is turned downwardly and thus hold the engaging levers in lockedengagement with the screw.

This screw driver is particularly adapted for use with a screw providedwith two wedge shaped recesses 28, 23 extending inwardly and downwardlytoward the diametrical center of the head of the screw, thereby leavinga central undercut connecting portion 24 which adds considerablestrength to the head of the screw and prevents a portion of the headbreaking off at the slot, as

in ordinary screws in which the slot extends 110 entirely across thehead.

The undercut portions of the head provide means for engagement with thewedge shaped clamping jaws of the engaging levers to draw the screwwedgingly against the lower end of the head of the driver and to preventits accidentally becoming disengaged therefrom. A round headed screw mayalso be provided with these wedge shaped recesses to adapt it for usewith the driver as clearly shown in Fig. 5. of the drawings, and thelower end of the driver head is provided with a concave recess toaccommodate the rounded portion of the screw head. In operation thefinger portions of the engaging levers are pressed together. Thismovement will open the wedge shaped jaws and permit them to engage thewedge shaped recesses in the head of the screw. By removing the pressurefrom the finger portions the coiled spring will force them apart andcause the jaws to close and draw the screw head tightly against the endof the head or the driver and will securely hold the screw in thisposition during the entire operation of driving it home into thematerial desired.

If it desired to lock the screw to the driver it is only necessary toturn the locking nut downwardly until the tapered end engages theengaging levers. The nut being in the path of movement of the leverswill prevent their being accidentally pressed together, and the screwwill be securely held between the jaws. It is obvious that the screwdriver may also engage a screw which is already in engagement forwithdrawal. The

wedge shaped aws are so shaped that they may be conveniently used forboring a tapered hole when it is desired to countersink the head of ascrew.

\Vhat I claim as my invention is:

A screw driver, comprising a shank provided with a head of substantiallythe same diameter as the head of a screw to which it is adapted toengage, and the lower portion of the shank positioned to bear on theupper surface of the screw, longitudinal recesses, transverse openingsand an end recess provided in said head, engaging levers disposed withinsaid recesses and being substantially flush with the outer diameter ofthe head and having a portion extending into one of the openings, saidlevers being reinforced by the side walls of the recesses, pivot pinspivotally connecting the levers to the head, vertically and horizontallytapering aws formed on the lower ends of the levers and extendingdownwardly and inwardly therefrom and adapted to engage the head of ascrew disposed in the end recess of the head, said jaws engaging thescrew head above the lower surface of the head, and a coiled springinterposed between the upper ends of the levers and extending throughone of the transverse openings.

In testimony whereof, I afliX my signature,

in presence of two witnesses.

' ALBERT N. BENDER.

itnesses A. L. MonsELL, ANNA F. SCHMIDTBAUER.

